The present invention relates to structural materials designed to minimize or remove internal or external vibrations which will effect a device, instrument, circuit board mechanism, object, or matter or parts thereof in an undesired manner. Specifically, fibrous reinforcing materials exhibiting high strength and high tensile modulus or other reinforcements with equivalent characteristics or as required internally or externally applied in strands, single, or multiple layers or other forms to a substrate, mass, or core of thermosetting resin, plastic, metal, or other material with high density or high strength or tensile modulus by nature or manufacture. Used in conjunction with devices to separate and additionally isolate a structure from vibrations produced by or through external structures or internal substructures, such material may be used as free standing isolation platforms such as table tops, shelves, or bases for use with existing equipment, instruments, devices, objects or matter sensitive to vibration or may be used as a primary structural member such as a chassis or secondary substructural members such as circuit boards or isolation platforms within such equipment or devices to isolate specific parts or sections thereof. The rigidity and resonance characteristics of the structures can be adapted as required, by altering the selected reinforcing material or materials, the tensile modulus, orientation or thickness or number of layers of the reinforcing material, the modulus characteristics of the resin or bonding agent, the modulus characteristics of the core, the core section thickness, the internal core section reinforcement, the weight of the core via perforations or by using lower specific gravity materials, and other means. A structure adjusted to the application will reduce or dampen the undesired effects of vibration and therefore will improve the resolution, accuracy, and efficiency of devices or objects to which they are applied or in which they are used.
The materials of the present invention have a wide range of application, such as devices or objects used in the creation, recording or reproduction of sound including, but not limited to, devices such as tape or digital recorders, microphones, processors, digital to analogue or analogue to digital converters, amplifiers, preamplifiers, turntables, speakers, etc. The materials may also be used with musical instruments requiring contact with external surfaces for support, such as drums, keyboards, pianos, cellos, etc. The materials may also be used within such instruments or other instruments that do not require external support.
Further, the materials may be used within or in conjunction with devices including, but not limited to, medical instruments and devices, power supplies, computers, scientific instruments, measuring devices, lasers, optical devices, precision control devices, optical devices, satellites, or any electrical, acoustical, optical, mechanical or any other object, device or matter that may be effected by internal or external vibrations in an undesired manner.
The prior art known to the inventor has to date consisted of three primary approaches to dealing with vibration problems: the application of viscoelastic polymers either alone or in a constrained layer format, laminations primarily consisting of lightweight or honeycomb core materials with high modulus skins, or mass loaded platforms such as granite, marble, concrete, or lead. These approaches may be effective to some degree or for specific vibrational frequencies, but each has its own limitations.
Viscoelastic or constrained layer polymers applied to an existing structure are by definition attempting to minimize the negative effects of vibration after they already exist within the component or device, instead of preventing or precluding them from entering the device at the outset. A laminated section with a lightweight core material may be rigid but may well lack sufficient mass and internal damping characteristics. One means to compensate for these inherent characteristics is to create core sections of formed metal or similar materials that are of great thickness (typically two or more inches) possibly incorporating internal dampening mechanisms and to laminate such a core section with high tensile modulus surface materials. These are frequently bulky, quite expensive and impractical for incorporation within components and devices. Granite, marble, concrete or structures of similar materials have the necessary mass but lack the necessary rigidity and internal dampening characteristics to itself be highly resistant to resonance and vibration, nor do they typically have electrical shielding properties. In an attempt to compensate for this inadequacy, large sections of the material are used resulting in large, heavy sections which are also expensive and in many situations impractical. In addition, devices to decouple platforms or components from external substructures have generally been limited to viscoelastic polymers or other damping materials having large contact areas with external surfaces, cones or feet made of non-reinforced plastic, metal, or cast resin materials, or elaborate dampening devices that are costly to execute. It has been desired to develop damping materials and structures that are more effective in performance with wide ranging applications, versatile in size and weight, practical to use, practical to fabricate, and cost effective to produce. It was with this background the development of the present invention took place.
The prior art with regard to chassis or structures for components or devices has consisted primarily of formed sheet steel, aluminum, other metals, or non-reinforced plastic (typically injection molded). All are highly susceptible to resonance, and are frequently treated with viscoelastic polymers in an attempt to counteract their inherent flaws. There is an occasional piece that incorporates a high density material such as granite or non-reinforced thermoset resin as an improved, but not ideal, structure.
Circuit boards are conventionally fiberglass structures that fail to take advantage of higher modulus reinforcing materials, nor are they designed with the intent of producing an inherently damped structure or material.
The goal of the present invention is to develop a system of structural and/or methodological alternatives to the solutions for vibration problems which are currently available. The materials need to have merit in a wide variety of applications, including as primary structures, substructures, application in harsh environments, etc. A further goal is for the materials to be able to accommodate the potential of large scale production or fabrication at a reasonable cost, and the capability of incorporating threaded inserts, bolt holes, and the like for practical use as component chassis, circuit boards, etc. As a result of these rather unusual demands, the development of structures using high modulus reinforcements in addition to or in conjunction with of high density materials that could meet the practical demands of manufacture and fabrication was undertaken by the present inventor.
While not limiting myself to any particular theory, I believe that structures described and disclosed in the present invention derive their performance characteristics essentially by enhancing the performance characteristics of higher density materials that are inherently less prone to vibrational effects, possess high rates of internal dampening, and by using high tensile modulus materials appropriate to the application as additional reinforcement internally or externally as a constraining layer. The effects of this additional reinforcement or constraining layer may be varied as desired by adjusting the quantity or tensile modulus of the reinforcement or reinforcing layer. These affects may be further augmented by adding layers of similar or dissimilar materials thereon, and can be further adjusted by the shear strength, elongation fillers, and other characteristics of the resin or bonding agent employed or by the use of additional fillers. The overall structure can be fully optimized to the specific application by incorporating electrical shielding, high heat resistance, chemical resistance, etc. as required by means of external lamination, modifications to the resin or bonding agent, core material, etc.